#include <bits/stdc++.h>
using namespace std;
const int NMAX = 1e5;
const int MMAX = 5e5;

ifstream fin( "ciclueuler.in" );
ofstream fout( "ciclueuler.out" );

struct muchie{
  int nod, ind;
};
vector <muchie> edges[NMAX+1];
stack <int> cycle;
stack <int> finalCycle;
int viz[MMAX];
int main() {
  int n, m, i, a, b, node;
  fin >> n >> m;
  for( i = 0; i < m; i++ ) {
    fin >> a >> b;
    edges[a].push_back( { b, i } );
    edges[b].push_back( { a, i } );
  }
  node = 1;
  while( edges[node].size() == 0 )
    node++;
  cycle.push( node );
  while( cycle.size() ) {
    node = cycle.top();
    i = 0;
    while( i < edges[node].size() && viz[edges[node][i].ind] )
      i++;
    if( i < edges[node].size() ) {
      viz[edges[node][i].ind] = true;
      cycle.push( edges[node][i].nod );
    }
    else {
      finalCycle.push( node );
      cycle.pop();
    }
  }
  while( finalCycle.size() > 1 ) {
    fout << finalCycle.top() << " ";
    finalCycle.pop();
  }
  return 0;
}